Oil soluble dispersant additives useful in oleaginous compositions

ABSTRACT

Hydrocarbyl substituted C 4  to C 10  monounsaturated dicarboxylic acid, anhydrides or esters, e.g. polyisobutenyl succinic anhydride, preferably made by reacting polymer of C 2  to C 10  monoolefin, preferably polyisobutylene, having a molecular weight of about 1500 to 5,000, preferably with a C 4  to C 10  monounsaturated acid, anhydride or ester, preferably maleic anhydride, such that there are 1.05 to 1.25 dicarboxylic acid producing moieties per molecule of said olefin polymer used in the reaction mixture. The resulting materials are useful per se as oil additives, or may be further reacted with amines, alcohols, amino alcohols, boric acid, etc. to form dispersants.

This is a division of U.S. Ser. No. 07/755,603, filed Sep. 5, 1991, nowU.S. Pat. No. 6,127,321; which is a continuation of U.S. Ser. No.07/613,330, filed Nov. 8, 1990, abandoned; which is a continuation ofU.S. Ser. No. 07/488,320, filed Mar. 5, 1990, abandoned; which is acontinuation of U.S. Ser. No. 07/235,920, filed Aug. 23, 1988,abandoned; which is a continuation of U.S. Ser. No. 07/032,066, filedMar. 27, 1987, abandoned; which is a continuation of U.S. Ser. No.06/754,001, filed Jul. 11, 1985, abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to oil soluble dispersant additives useful infuel and lubricating oil compositions, including concentrates containingsaid additives, and methods for their manufacture and use. Thedispersant additives are dicarboxylic acids, anhydrides, esters, etc.,substituted with a high molecular weight hydrocarbon group, andderivatives thereof such as salts, amides, imides, esters, oxazolines,etc. formed by further reaction with amine, alcohol, amino alcohols, andwhich may be further treated, e.g. borated. The high molecular weighthydrocarbon group has a number average molecular weight ({overscore(M)}_(n)) of about 1500 to 5000. The additives will have a ratio(functionality) of about 1.05 to 1.25 dicarboxylic acid producingmoieties per said high molecular weight hydrocarbon used in thereaction.

2. Prior Disclosures

U.S. 4,234,435 discloses as oil additives, polyalkene substituteddicarboxylic acids derived from polyalkenes having a {overscore (M)}_(n)of 1300 to 5,000 and containing at least 1.3 dicarboxylic acid groupsper polyalkene.

Canadian Patent 895,398 discloses reacting a mole of an unsaturatedhydrocarbon group of 700 to 10,000 mol. wt. with 1 to 1.5 moles ofchloro-substituted maleic or fumaric acid, which material can then befurther reacted with alcohol.

U.S. Pat. No. 3,927,041 discloses a mole of polybutene of 300 to 3,000mol. wt. containing 5 to 200 ppm 1,3 dibromo-5.5-dialkylhydantoin as acatalyst reacted with 0.8 to 5, generally 1.05 to 1.15 moles ofdicarboxylic acid or anhydride, to form materials which can be used perse, or as esters, amides, imides, amidines, in petroleum products.

U.S. Pat. No. 3,215,707 discloses reacting chlorine with a mixture ofpolyolefin up to 50,000 molecular weight, especially of 250 to 3,000molecular weight with one or more moles of maleic anhydride dependingupon whether one or more succinic anhydride radicals are to be in eachpolymer molecule.

U.S. Pat. Nos. 4,113,639 and 4,116,876 disclose an example of alkenylsuccinic anhydride having a molecular weight of the alkenyl group of1300 and a Saponification Number of 103 (about 1.3 succinic anhydrideunits per hydrocarbon molecule. This alkenyl succinic anhydride may bereacted with polyamine and then boric acid (U.S. 4,113,639), or may bereacted with an amino alcohol to form an oxazoline (4,116,876) which isthen borated by reaction with boric acid.

U.S. Pat. No. 4,062,786 in Example 13 shows a polyisobutenylsuccinicanhydride of molecular weight of about 1300 and a Saponification Numberof about 100 (about 1.25 succinic anhydride units per alkenyl group).

U.S. Pat. No. 4,123,373 in Example 3 shows a polyisobutenylsuccinicanhydride of about 1400 molecular weight having a Saponification Numberof 80 (about 1.07 succinic anhydride units per polyisobutylene units.

Further related prior disclosures, which are expressly incorporatedherein by reference in their entirety are U.S. Pat. Nos.: 3,087,936;3,131,150; 3,154,560; 3,172,892; 3,198,736; 3,219,666; 3,231,587;3,235,484; 3,269,946; 3,272,743; 3,272,746; 3,278,550; 3,284,409;3,284,410; 3,288,714; 3,403,102; 3,562,159; 3,576,743; 3,632,510;3,836,470; 3,836,471; 3,838,050; 3,838,052; 3,879,308; 3,912,764;3,927,041; Re. 26,330; 4,110,349; 4,113,639; 4,151,173; 4,195,976; andU.K. Patents 1,368,277 and 1,398,008.

SUMMARY OF THE INVENTION

The present invention is directed to a dispersant additive comprising apolyolefin of 1500 to 5,000 number average molecular weight substitutedwith 1.05 to 1.25, preferably 1.06 to 1.20, e.g. 1.10 to 1.20dicarboxylic acid producing moieties, preferably acid or anhydridemoieties, per polyolefin molecule. This acid or anhydride material isuseful per se as an additive, e.g. a dispersant additive, for example inthe same manner as previously known polyolefin substituted dicarboxylicacid or anhydride acylating agents as disclosed in U.S. Pat. No.3,288,714 where prior acylating agents are used as dispersant/detergentsand U.S. Pat. No. 3,714,042 where prior acylating agents are used totreat overbased metal complexes. Also, the material of the invention canbe used in the manner described in U.S. Pat. No. 3,965,017 whereinoverbased detergents are treated with acylating agents. The dicarboxylicacid producing materials of the invention can also be further reactedwith amines, alcohols, including polyols, amino-alcohols, etc. to formother useful dispersant additives. Thus, if the acid producing materialis to be further reacted, e.g. neutralized, then generally a majorproportion of at least 50% of the acid units up to all the acid unitswill be reacted.

The materials of the invention are different from the prior art becauseof their effectiveness coupled with their low degree of interaction withother additives, as compared to those prior disclosures mentioned abovewhich have a functionality of 1.3 or more dicarboxylic acid producinggroups per hydrocarbon moiety used in the reaction.

Lubricating oil compositions, e.g. automatic transmission fluids, heavyduty oils suitable for gasoline and diesel engines, etc., can beprepared with the additives of the invention. Universal type crankcaseoils wherein the same lubricating oil compositions can be used for bothgasoline and diesel engine can also be prepared. These lubricating oilformulations conventionally contain several different types of additivesthat will supply the characteristics that are required in theformulations. Among these types of additives are included viscosityindex improvers, antioxidants, corrosion inhibitors, detergents,dispersants, pour point depressants, antiwear agents, etc.

In the preparation of lubricating oil formulations it is common practiceto introduce the additives in the form of 10 to 80 wt. %, e.g. 20 to 80wt. % active ingredient concentrates in hydrocarbon oil, e.g. minerallubricating oil, or other suitable solvent. Usually these concentratesmay be diluted with 3 to 40, e.g. 5 to 20 parts by weight of lubricatingoil, per part by weight of the additive package, in forming finishedlubricants, e.g. crankcase motor oils. The purpose of concentrates, isof course, to make the handling of the various materials less difficultand awkward as well as to facilitate solution or dispersion in the finalblend. Thus, a metal hydrocarbyl sulfonate or a metal alkyl phenatewould be usually employed in the form of a 40 to 50 wt. % concentrate,for example, in a lubricating oil fraction. Ordinarily when preparing alubricating oil blend that contains several types of additives noproblems arise where each additive is incorporated separately in theform of a concentrate in oil. In many instances, however, the additivesupplier will want to make available an additive “package” comprising anumber of additives in a single concentrate in a hydrocarbon oil orother suitable solvent. Some additives tend to react with each other inan oil concentrate. Dispersants having a functionality (ratio) of 1.3 orhigher, of the dicarboxylic acid moieties per hydrocarbon molecule havebeen found to interact with various other additives in packages,particularly overbased metal detergents to cause a viscosity increaseupon blending, which may be followed by a subsequent growth or increaseof viscosity with time in some instances resulting in gellation of theblend. This viscosity increase can hamper pumping, blending and handlingof the concentrate. While the package can be further diluted with morediluent oil to reduce the viscosity to offset the interaction effect,this dilution reduces the economy of using the package by increasingshipping, storage and other handling costs. The materials of the presentinvention with a functionality below 1.25:1 minimize this viscosityinteraction while achieving an effective additive. The compositiondescribed represents an additional improvement in that the hydrocarbonpolymer required to maintain the oil solubility of the dispersant duringengine operation can be provided with fewer acylating units perpolyamine. For example, a typical dispersant derived from a polybuteneacylating agent with a functionality of 1.3 or more dicarboxylic acidgroups per polymer, condensed with a polyethyleneamine containing 4-7nitrogen atoms per molecule, would require two or more acylating unitsper polyamine to provide sufficient oil solubility for adequatedispersancy in gasoline and diesel engines. Reducing the functionalitybelow 1.25 generates the requisite ratio of oil-soluble polymer perpolyamine at a lower relative stoichiometry of acylating agent perpolyamine. Thus, a dispersant derived from a polybutene acylating agentwith a functionality of 1.05 condensed with a 5-nitrogenpolyethyleneamine in a ratio of 1.5 to 1 contains approximately the sameratio of non-polar to polar groupings as a dispersant made from apolybutene acylating agent with a functionality of 1.4 condensed withthe same polyamine in a ratio of 2:1. The former composition would beconsiderably lower in viscosity and exhibit reduced interactionsrelative to the latter.

THE HYDROCARBYL DICARBOXYLIC ACID MATERIAL

The long chain hydrocarbyl substituted dicarboxylic acid material, i.e.acid or anhydride, or ester, used in the invention includes long chainhydrocarbon, generally a polyolefin, substituted with 1.05 to 1.25,preferably 1.06 to 1.20, e.g. 1.10 to 1.20 moles, per mole of polyolefinof an alpha or beta unsaturated C₄ to C₁₀ dicarboxylic acids, oranhydrides or esters thereof, such as fumaric acid, itaconic acid,maleic acid, maleic anhydride, chloromaleic acid, dimethyl fumarate,chloromaleic anhydride, etc.

Preferred olefin polymers for reaction with the unsaturated dicarboxylicacids are polymers comprising a major molar amount of C₂ to C₁₀, e.g. C₂to C₅ monoolefin. Such olefins include ethylene, propylene, butylene,isobutylene, pentene, octene-1, styrene, etc. The polymers can behomopolymers such as polyisobutylene, as well as copolymers of two ormore of such olefins such as copolymers of: ethylene and propylene;butylene and isobutylene; propylene and isobutylene; etc. Othercopolymers include those in which a minor molar amount of the copolymermonomers, e.g., 1 to 10 mole %, is a C₄ to C₁₈ non-conjugated diolefin,e.g., a copolymer of isobutylene and butadiene; or a copolymer ofethylene, propylene and 1,4-hexadiene; etc.

In some cases, the olefin polymer may be completely saturated, forexample an ethylene-propylene copolymer made by a Ziegler-Nattasynthesis using hydrogen as a moderator to control molecular weight.

The olefin polymers will usually have number average molecular weightswithin the range of about 1500 and about 5,000, more usually betweenabout 1600 and about 3000. Particularly useful olefin polymers havenumber average molecular weights within the range of about 1500 andabout 2500 with approximately one terminal double bond per polymerchain. An especially useful starting material for a highly potentdispersant additive made in accordance with this invention ispolyisobutylene. The number average molecular weight for such polymerscan be determined by several known techniques. A convenient method forsuch determination is by gel permeation chromatography (GPC) whichadditionally provides molecular weight distribution information, see W.W. Yau, J. J. Kirkland and D. D. Bly, “Modern Size Exclusion LiquidChromatography”, John Wiley and Sons, New York, 1979.

Processes for reacting the olefin polymer with the C₄₋₁₀ unsaturateddicarboxylic acid, anhydride or ester are known in the art. For example,the olefin polymer and the dicarboxylic acid material may be simplyheated together as disclosed in U.S. Pat. Nos. 3,361,673 and 3,401,118to cause a thermal “ene” reaction to take place. Or, the olefin polymercan be first halogenated, for example, chlorinated or brominated toabout 1 to 8, preferably 3 to 7 wt. % chlorine, or bromine, based on theweight of polymer, by passing the chlorine or bromine through thepolyolefin at a temperature of 100 to 250, e.g. 140 to 225° C. for about0.5 to 10, preferably 1 to 7 hours. The halogenated polymer may then bereacted with sufficient unsaturated acid or anhydride at 100 to 250,usually about 140 to 180° C. for about 0.5 to 10, e.g. 3 to 8 hours, sothe product obtained will contain about 1.05 to 1.25, preferably 1.06 to1.20, e.g. 1.10 moles of the unsaturated acid per mole of thehalogenated polymer. Processes of this general type are taught in U.S.Pat. Nos. 3,087,436; 3,172,892; 3,272,746 and others.

Alternatively, the olefin polymer, and the unsaturated acid material aremixed and heated while adding chlorine to the hot material. Processes ofthis type are disclosed in U.S. Pat. Nos. 3,215,707; 3,231,587;3,912,764; 4,110,349; 4,234,435; and in U.K. 1,440,219.

By the use of halogen, about 65 to 95 wt. % of the polyolefin, e.g.polyisobutylene will normally react with the dicarboxylic acid material.Upon carrying out a thermal reaction without the use of halogen or acatalyst, then usually only about 50 to 75 wt. % of the polyisobutylenewill react. Chlorination helps increase the reactivity. For convenience,the aforesaid functionality ratios of dicarboxylic acid producing unitsto polyolefin of 1.05 to 1.25; 1.06 to 1.20 and 1.10 to 1.20 are basedupon the total amount of polyolefin, that is, the total of both thereacted and unreacted polyolefin, used to make the product.

NITROGEN AND ALCOHOL ASHLESS DISPERSANT DERIVATIVES

Useful amine compounds for neutralization of the hydrocarbyl substituteddicarboxylic acid material include mono-and polyamines of about 2 to 60,e.g. 3 to 20, total carbon atoms and about 1 to 12, e.g., 2 to 8nitrogen atoms in the molecule. These amines may be hydrocarbyl aminesor may be hydrocarbyl amines including other groups, e.g, hydroxygroups, alkoxy groups, amide groups, nitriles, imidazoline groups, andthe like. Hydroxy amines with 1 to 6 hydroxy groups, preferably 1 to 3hydroxy groups are particularly useful. Preferred amines are aliphaticsaturated amines, including those of the general formulas:

wherein R, R′ and R″ are independently selected from the groupconsisting of hydrogen; C₁ to C₂₅ straight or branched chain alkylradicals; C₁ to C₁₂ alkoxy C₂ to C₆ alkylene radicals; C₂ to C₁₂ hydroxyamino alkylene radicals; and C₁ to C₁₂ alkylamino C₂ to C₆ alkyleneradicals; each s can be the same or a different number of from 2 to 6,preferably 2 to 4; and t is a number of from 0 to 10, preferably 2 to 7.

Non-limiting examples of suitable amine compounds include:1,2-diaminoethane; 1,3-diaminopropane; 1,4-diaminobutane;1,6-diaminohexane; polyethylene amines such as diethylene triamine;triethylene tetramine; tetraethylene pentamine; polypropylene aminessuch as 1,2-propylene diamine; di-(1,2-propylene)triamine;di-(1,3-propylene) triamine; N,N-dimethyl-1,3-diaminopropane;N,N-di-(2-aminoethyl) ethylene diamine;N,N-di(2-hydroxyethyl)-1,3-propylene diamine; 3-dodecyloxy-propylamine;N-dodecyl-1,3-propane diamine; tris hydroxy-methylaminomethane (THAM);diisopropanol amine; diethanol amine; triethanol amine; mono-, di-, andtri-tallow amines; amino morpholines such asN-(3-aminopropyl)mor-pholine; etc.

Other useful amine compounds include: alicyclic diamines such as1,4-di(aminomethyl) cyclohexane, and heterocyclic nitrogen compoundssuch as imidazolines, and N-aminoalkyl piperazines of the generalformula:

wherein G is independently selected from the group consisting ofhydrogen and omega-aminoalkylene radicals of from 1 to 3 carbon atoms,and p is an integer of from 1 to 4. Non-limiting examples of such aminesinclude 2-pentadecyl imidazoline; N-(2-aminoethyl) piperazine; etc.

Commercial mixtures of amine compounds may advantageously be used. Forexample, one process for preparing alkylene amines involves the reactionof an alkylene dihalide (such as ethylene dichloride or propylenedichloride) with ammonia, which results in a complex mixture of alkyleneamines wherein pairs of nitrogens are joined by alkylene groups, formingsuch compounds as diethylene triamine, triethylenetetramine,tetraethylene pentamine and isomeric piperazines. Low costpoly(ethyleneamines) compounds averaging about 5 to 7 nitrogen atoms permolecule are available commercially under trade names such as “PolyamineH”, “Polyamine 400”, “Dow Polyamine E-100”, etc.

Useful amines also include polyoxyalkylene polyamines such as those ofthe formulae:

where m has a value of about 3 to 70 and preferably 10 to 35; and:

where n has a value of about 1 to 40 with the provision that the sum ofall the n's is from about 3 to about 70 and preferably from about 6 toabout 35 and R is a polyvalent saturated hydrocarbon radical of up toten carbon atoms having a valence of 3 to 6. The alkylene groups ineither formula (i) or (ii) may be straight or branched chains containingabout 2 to 7, and preferably about 2 to 4 carbon atoms.

The polyoxyalkylene polyamines of formula (B) above, preferablypolyoxyalkylene diamines and polyoxyalkylene triamines, may have averagemolecular weights ranging from about 200 to about 4000 and preferablyfrom about 400 to about 2000. The preferred polyoxyalkylene polyaminesinclude the polyoxyethylene and polyoxypropylene diamines and thepolyoxypropylene triamines having average molecular weights ranging fromabout 200 to 2000. The polyoxyalkylene polyamines are commerciallyavailable and may be obtained, for example, from the Jefferson ChemicalCompany, Inc. under the trade name “Jeffamines D-230, D-400, D-1000,D-2000, T-403”, etc.

The amine is readily reacted with the dicarboxylic acid material, e.g.alkenyl succinic anhydride, by heating an oil solution containing 5 to95 wt. % of dicarboxylic acid material to about 100 to 250° C.,preferably 125 to 175° C., generally for 1 to 10, e.g. 2 to 6 hoursuntil the desired amount of water is removed. The heating is preferablycarried out to favor formation of imides or mixtures of imides andamides, rather than amides and salts. Reaction ratios can varyconsiderably, depending upon the reactants, amounts of excess amine,type of bonds formed, etc. Generally from 0.3 to 2, preferably about 0.3to 1.0, e.g. 0.4 to 0.8 mole of amine, e.g. bi-primary amine is used,per mole of the dicarboxylic acid moiety content e.g. grafted maleicanhydride content. For example, one mole of olefin reacted withsufficient maleic anhydride to add 1.10 mole of maleic anhydride groupsper mole of olefin when converted to a mixture of amides and imides,about 0.55 moles of amine with two primary groups would preferably beused, i.e. 0.50 mole of amine per mole of dicarboxylic acid moiety.

The nitrogen containing dispersant can be further treated by boration asgenerally taught in U.S. Pat. Nos. 3,087,936 and 3,254,025 (incorporatedherein by reference thereto). This is readily accomplished by treatingsaid acyl nitrogen dispersant with a boron compound selected from theclass consisting of boron oxide, boron halides, boron acids and estersof boron acids in an amount to provide from about 0.1 atomic proportionof boron for each mole of said acylated nitrogen composition to about 10atomic proportions of boron for each atomic proportion of nitrogen ofsaid acylated nitrogen composition. Usefully the dispersants of theinventive combination contain from about 0.05 to 2.0 wt. %, e.g. 0.05 to0.7 wt. % boron based on the total weight of said borated acyl nitrogencompound. The boron, which appears to be in the product as dehydratedboric acid polymers (primarily (HBO₂)₃), is believed to attach to thedispersant imides and diimides as amine salts e.g. the metaborate saltof said diimide.

Treating is readily carried out by adding from about 0.05 to 4, e.g. 1to 3 wt. % (based on the weight of said acyl nitrogen compound) of saidboron compound, preferably boric acid which is most usually added as aslurry to said acyl nitrogen compound and heating with stirring at fromabout 135° C. to 190, e.g. 140-170° C., for from 1 to 5 hours followedby nitrogen stripping at said temperature ranges. Or, the borontreatment can be carried out by adding boric acid to the hot reactionmixture of the dicarboxylic acid material and amine while removingwater.

The tris(hydroxymethyl) amino methane (THAM) can be reacted with theaforesaid acid material to form amides, imides or ester type additivesas taught by U.K. 984,409, or to form oxazoline compounds and boratedoxazoline compounds as described, for example, in U.S. Pat. Nos.4,102,798; 4,116,876 and 4,113,639.

The ashless dispersants may also be esters derived from the aforesaidlong chain hydrocarbon substituted dicarboxylic acid material and fromhydroxy compounds such as monohydric and polyhydric alcohols or aromaticcompounds such as phenols and naphthols, etc. The polyhydric alcoholsare the most preferred hydroxy compound and preferably contain from 2 toabout 10 hydroxy radicals, for example, ethylene glycol, diethyleneglycol, triethylene glycol, tetraethylene glycol, dipropylene glycol,and other alkylene glycols in which the alkylene radical contains from 2to about 8 carbon atoms. Other useful polyhydric alcohols includeglycerol, mono-oleate of glycerol, monostearate of glycerol, monomethylether of glycerol, pentaerythritol, dipentaerythritol, etc.

The ester dispersant may also be derived from unsaturated alcohols suchas allyl alcohol, cinnamyl alcohol, propargyl alcohol,1-cyclohexane-3-ol, and oleyl alcohol. Still other classes of thealcohols capable of yielding the esters of this invention comprise theether-alcohols and amino-alcohols including, for example, theoxy-alkylene, oxy-arylene-, amino-alkylene-, andamino-arylene-substituted alcohols having one or more oxy-alkylene,amino-alkylene or amino-arylene oxy-arylene radicals. They areexemplified by Cellosolve, Carbitol, N,N,N′,N′-tetrahydroxy-trimethylenedi-amine, and ether-alcohols having up to about 150 oxy-alkyleneradicals in which the alkylene radical contains from 1 to about 8 carbonatoms.

The ester dispersant may be di-esters of succinic acids or acidicesters, i.e., partially esterified succinic acids; as well as partiallyesterified polyhydric alcohols or phenols, i.e., esters having freealcohols or phenolic hydroxyl radicals. Mixtures of the aboveillustrated esters likewise are contemplated within the scope of thisinvention.

The ester dispersant may be prepared by one of several known methods asillustrated for example in U.S. Pat. No. 3,522,179.

Hydroxyamines which can be reacted with the aforesaid long chainhydrocarbon substituted dicarboxylic acid material to form dispersantsinclude 2-amino-1-butanol, 2-amino-2-methyl-1-propanol,p-(beta-hydroxy-ethyl)-aniline, 2-amino-1-propanol, 3-amino-1-propanol,2-amino-2-methyl-1, 3-propane-diol, 2-amino-2-ethyl-1, 3-propanediol,N-(beta-hydroxy-propyl)-N′-(beta-amino-ethyl)-piperazine,tris(hydroxymethyl) amino-methane (also known astrismethylolaminomethane), 2-amino-1-butanol, ethanolamine,beta-(beta-hydroxyethoxy)-ethylamine, and the like. Mixtures of these orsimilar amines can also be employed.

The preferred dispersants are those derived from polyisobutylenesubstituted with succinic anhydride groups and reacted with polyethyleneamines, e.g. tetraethylene pentamine, pentaethylene hexamine,polyoxyethylene and polyoxypropylene amines, e.g. polyoxypropylenediamine, trismethylolaminomethane and pentaerythritol, and combinationsthereof. One particularly preferred dispersant combination involves acombination of (A) polyisobutene substituted with succinic anhydridegroups and reacted with (B) a hydroxy compound, e.g. pentaerythritol,(C) a polyoxyalkylene polyamine, e.g. polyoxypropylene diamine, and (D)a polyalkylene polyamine, e.g. polyethylene diamine and tetraethylenepentamine using about 0.3 to about 2 moles each of (B) and (D) and about0.3 to about 2 moles of (C) per mole of (A) as described in U.S. Pat.No. 3,804,763. Another preferred dispersant combination involves thecombination of (A) polyisobutenyl succinic anhydride with (B) apolyalkylene polyamine, e.g. tetraethylene pentamine, and (C) apolyhydric alcohol or polyhydroxy-substituted aliphatic primary amine,e.g. pentaerythritol or trismethylolaminomethane as described in U.S.Pat. No. 3,632,511.

THE METAL RUST INHIBITORS AND DETERGENTS

Metal containing rust inhibitors and/or detergents are frequently usedwith ashless dispersants. Such detergents and rust inhibitors includethe metal salts of sulphonic acids, alkyl phenols, sulphurized alkylphenols, alkyl salicylates, naphthenates, and other oil soluble mono-and di-carboxylic acids. Highly basic, that is overbased metal saltswhich are frequently used as detergents appear particularly prone tointeraction with the ashless dispersant. Usually these metal containingrust inhibitors and detergents are used in lubricating oil in amounts ofabout 0.01 to 10, e.g. 0.1 to 5 wt. %, based on the weight of the totallubricating composition.

Highly basic alkaline earth metal sulfonates are frequently used asdetergents. They are usually produced by heating a mixture comprising anoil-soluble sulfonate or alkaryl sulfonic acid, with an excess ofalkaline earth metal compound above that required for completeneutralization of any sulfonic acid present and thereafter forming adispersed carbonate complex by reacting the excess metal with carbondioxide to provide the desired overbasing. The sulfonic acids aretypically obtained by the sulfonation of alkyl substituted aromatichydrocarbons such as those obtained from the fractionation of petroleumby distillation and/or extraction or by the alkylation of aromatichydrocarbons as for example those obtained by alkylating benzene,toluene, xylene, naphthalene, diphenyl and the halogen derivatives suchas chlorobenzene, chlorotoluene and chloronaphthalene. The alkylationmay be carried out in the presence of a catalyst with alkylating agentshaving from about 3 to more than 30 carbon atoms such as for examplehaloparaffins, olefins that may be obtained by dehydrogenation ofparaffins, polyolefins as for example polymers from ethylene, propylene,etc. The alkaryl sulfonates usually contain from about 9 to about 70 ormore carbon atoms, preferably from about 16 to about 50 carbon atoms peralkyl substituted aromatic moiety.

The alkaline earth metal compounds which may be used in neutralizingthese alkaryl sulfonic acids to provide the sulfonates includes theoxides and hydroxides, alkoxides, carbonates, carboxylate, sulfide,hydrosulfide, nitrate, borates and ethers of magnesium, calcium, andbarium. Examples are calcium oxide, calcium hydroxide, magnesium acetateand magnesium borate. As noted, the alkaline earth metal compound isused in excess of that required to complete neutralization of thealkaryl sulfonic acids. Generally, the amount ranges from about 100 to220%, although it is preferred to use at least 125%, of thestoichiometric amount of metal required for complete neutralization.

Various other preparations of basic alkaline earth metal alkarylsulfonates are known, such as U.S. Pat. Nos. 3,150,088 and 3,150,089wherein overbasing is accomplished by hydrolysis of analkoxide-carbonate complex with the alkaryl sulfonate in a hydrocarbonsolventdiluent oil.

A preferred alkaline earth sulfonate additive is magnesium alkylaromatic sulfonate having a total base number ranging from about 300 toabout 400 with the magnesium sulfonate content ranging from about 25 toabout 32 wt. %, based upon the total weight of the additive systemdispersed in mineral lubricating oil.

Neutral metal sulfonates are frequently used as rust inhibitors.Polyvalent metal alkyl salicylate and naphthenate materials are knownadditives for lubricating oil compositions to improve their hightemperature performance and to counteract deposition of carbonaceousmatter on pistons (U.S. Pat. No. 2,744,069). An increase in reservebasicity of the polyvalent metal alkyl salicylates and naphthenates canbe realized by utilizing alkaline earth metal, e.g. calcium, salts ofmixtures of C₈-C₂₆ alkyl salicylates and phenates (see U.S. Pat. No.2,744,069) or polyvalent metal salts of alkyl salicyclic acids, saidacids obtained from the alkylation of phenols followed by phenation,carboxylation and hydrolysis (U.S. Pat. No. 3,704,315) which could thenbe converted into highly basic salts by techniques generally known andused for such conversion. The reserve basicity of these metal-containingrust inhibitors is usefully at TBN levels of between about 60 and 150.Included with the useful polyvalent metal salicylate and naphthenatematerials are the methylene and sulfur bridged materials which arereadily derived from alkyl substituted salicylic or naphthenic acids ormixtures of either or both with alkyl substituted phenols. Basicsulfurized salicylates and a method for their preparation is shown inU.S. Pat. No. 3,595,791. Such materials include alkaline earth metal,particularly magnesium, calcium, strontium and barium salts of aromaticacids having the general formula:

HOOC—ArR₁—Xy(ArR₁OH)_(n)

where Ar is an aryl radical of 1 to 6 rings, R₁ is an alkyl group havingfrom about 8 to 50 carbon atoms, preferably 12 to 30 carbon atoms(optimally about 12), X is a sulfur (—S—) or methylene (—CH₂—) bridge, yis a number from 0 to 4 and n is a number from 0 to 4.

Preparation of the overbased methylene bridged salicylate-phenate saltis readily carried out by conventional techniques such as by alkylationof a phenol followed by phenation, carboxylation, hydrolysis, methylenebridging a coupling agent such as an alkylene dihalide followed by saltformation concurrent with carbonation. An overbased calcium salt of amethylene bridged phenol-salicylic acid of the general formula:

with a TBN of 60 to 150 is highly useful in this invention.

The sulfurized metal phenates can be considered the “metal salt of aphenol sulfide” which thus refers to a metal salt whether neutral orbasic, of a compound typified by the general formula:

where x=1 or 2, n=0, 1 or 2

or a polymeric form of such a compound, where R is an alkyl radical, nand x are each integers from 1 to 4, and the average number of carbonatoms in all of the R groups is at least about 9 in order to ensureadequate solubility in oil. The individual R groups may each containfrom 5 to 40, preferably 8 to 20, carbon atoms. The metal salt isprepared by reacting an alkyl phenol sulfide with a sufficient quantityof metal containing material to impart the desired alkalinity to thesulfurized metal phenate.

Regardless of the manner in which they are prepared, the sulfurizedalkyl phenols which are useful generally contain from about 2 to about14% by weight, preferably about 4 to about 12 wt. % sulfur based on theweight of sulfurized alkyl phenol.

The sulfurized alkyl phenol may be converted by reaction with a metalcontaining material including oxides, hydroxides and complexes in anamount sufficient to neutralize said phenol and, if desired, to overbasethe product to a desired alkalinity by procedures well known in the art.Preferred is a process of neutralization utilizing a solution of metalin a glycol ether.

The neutral or normal sulfurized metal phenates are those in which theratio of metal to phenol nucleus is about 1:2. The “overbased” or“basic” sulfurized metal phenates are sulfurized metal phenates whereinthe ratio of metal to phenol is greater than that of stoichiometric,e.g. basic sulfurized metal dodecyl phenate has a metal content up toand greater than 100% in excess of the metal present in thecorresponding normal sulfurized metal phenates wherein the excess metalis produced in oil-soluble or dispersible form (as by reaction withCO₂).

Another class of additive that can interact with ashless dispersants arethe dihydrocarbyl dithiophosphate metal salts which are frequently usedas antiwear agents and which also provide anti-oxidant activity. Thezinc salts are most commonly used in lubricating oil in amounts of 0.1to 10, preferably 0.2 to 2 wt. %, based upon the total weight of thelubricating oil composition. They may be prepared in accordance withknown techniques by first forming a dithiophosphoric acid, usually byreaction of an alcohol or a phenol with P₂S₅ and then neutralizing thedithiophosphoric acid with a suitable zinc compound.

Mixtures of alcohols may be used including mixtures of primary andsecondary alcohols, secondary generally for imparting improved antiwearproperties, with primary giving improved thermal stability properties.Mixtures of the two are particularly useful. In general, any basic orneutral zinc compound could be used but the oxides, hydroxides andcarbonates are most generally employed. Commercial additives frequentlycontain an excess of zinc due to use of an excess of the basic zinccompound in the neutralization reaction.

The zinc dihydrocarbyl dithiophosphates useful in the present inventionare oil soluble salts of dihydrocarbyl esters of dithiophosphoric acidsand may be represented by the following formula:

wherein R and R′ may be the same or different hydrocarbyl radicalscontaining from 1 to 18, preferably 2 to 12 carbon atoms and includingradicals such as alkyl, alkenyl, aryl, aralkyl, alkaryl andcycloaliphatic radicals. Particularly preferred as R and R′ groups arealkyl groups of 2 to 8 carbon atoms. Thus, the radicals may, forexample, be ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl,amyl, n-hexyl, i-hexyl, n-octyl, decyl, dodecyl, octadecyl,2-ethylhexyl, phenyl, butyl-phenyl, cyclohexyl, methylcyclopentyl,propenyl, butenyl etc. In order to obtain oil solubility, the totalnumber of carbon atoms (i.e. R and R′) in the dithiophosphoric acid willgenerally be about 5 or greater.

The Compositions

The dispersant products of this invention, that is the dicarboxylic acidproducing material per se, or the product of said dicarboxylic acidproducing material further reacted with amine, alcohol, amino alcohol,mixtures thereof, etc. can be incorporated in lubricating oilcompositions, e.g. automotive crankcase lubricating oils, inconcentrations within the range of about 0.01 to 15 weight percent, e.g.0.1 to 10 weight percent, preferably 0.2 to 7.0 weight percent, based onthe weight of the total compositions. The lubricants to which theproducts of this invention can be added include not only hydrocarbonoils derived from petroleum but also include synthetic oils such asalkyl esters of dicarboxylic acids, polyglycols and alcohols;polyalphaolefins, alkyl benzenes, organic esters of phosphoric acids,polysilicone oil, etc.

When the products of this invention are used as dispersants in normallyliquid petroleum fuels such as gasoline, and middle distillates boilingfrom about 150° to 800° F., including kerosene, diesel fuels, homeheating fuel oil, jet fuels, etc., a concentration of the additive inthe fuel in the range of 0.001 to 0.5, preferably about 0.001 to 0.1weight percent, based on the weight of the total composition, willusually be employed.

The additive may be conveniently dispensed as a concentrate comprising 5to 70 wt. % of the dispersant, with 95 to 30 wt. % oil. More usually, aminor proportion of the additive, e.g. 5 to up to 50 wt. %., isdissolved in a major proportion of a mineral lubricating oil , e.g. 50%,to 95 wt. %, with or without other additives being present. Thedispersant additive can also be used in lubricating oil additivepackages, particularly those containing metal detergents. These packageswill generally contain about 20 to 80 wt. % mineral lubricating oil andabout 20 to 80, e.g. 40 to 60 wt. % dispersant additive. The package mayfurther contain about 3 to 50, e.g. 3 to 40, preferably 5 to 25, e.g. 10to 20 wt. % of the metal detergent. It may also contain about 3 to 40,preferably 5 to 25, e.g. 10 to 20 wt. % of zinc dithiophosphate. All ofsaid weight percents of dispersant, metal detergent and zincdithiophosphate additive being based upon the total weight of theadditive package.

In the above compositions, concentrates or packages, other conventionaladditives may also be included, such as pour point depressants, antiwearagents such as tricresyl phosphate or zinc dithiophophates, antioxidantssuch as N-phenyl α-naphthylamine, t.-octyl phenol sulfide,4,4′-methylene bis(2,6-di-tertbutyl phenol), viscosity index improverssuch as ethylene-propylene copolymers, polymethacrylates,polyisobutylene, alkyl fumarate-vinyl acetate copolymers and the like,as well as other ashless dispersants such as other polyisobutylenesuccinic anhydrides reacted with amines, hydroxy amines, polyols, etc.

This invention will be further understood by reference to the followingexamples, wherein all parts are parts by weight, unless otherwise notedand which include preferred embodiments of the invention.

EXAMPLE 1

Part A

A polyisobutenyl succinic anhydride (PIBSA) having a SA:PIB ratio of1.04 succinic anhydride (SA) moieties per polyisobutylene (PIB) moleculeof 1725 {overscore (M)}_(n) was prepared by heating a mixture of 100parts of polyisobutylene with 7.55 parts of maleic anhydride to atemperature of about 220° C. When the temperature reached 120° C., thechlorine addition was begun and 5.88 parts of chlorine at a constantrate was added to the hot mixture for about 5.5 hours. The reactionmixture was then heat soaked at 220° C. for about 1.5 hours and thenstripped with nitrogen for about one hour. The resulting polyiso-butenylsuccinic anhydride had an ASTM Saponification Number of 64.2 whichcalculates to a succinic anhydride (SA) to polyisobutylene (PIB) ratioof 1.04 based upon starting PIB as follows:$\text{SA:PIB~~~ratio} = {\frac{1725 \times 64.2}{\left( {112200 - {64.2 \times 96}} \right)} = 1.04}$

The PIBSA product was 83.8 wt. % active ingredient (a.i.), the remainderbeing primarily unreacted PIB. The SA:PIB ratio of 1.04 is based uponthe total PIB charged to the reactor as starting material, i.e. both thePIB which reacts and the PIB which remains unreacted.

Part B

The PIBSA of Part A was aminated and borated as follows:

1800 g of the PIBSA having a Sap. No. of 64.2 and 1317 g of S150Nlubricating oil (solvent neutral oil having a viscosity of about 150SUSat 100° C.) was mixed in a reaction flask and heated to about 149° C.Then 121.9 g of a commercial grade of polyethyleneamine (hereinafterreferred to as PAM) which was a mixture of polyethyleneamines averagingabout 5 to 7 nitrogens per molecule was added and the mixture heated to149° C. for about one hour, followed by nitrogen stripping for about 1.5hours. Next, 49 g of boric acid was added over about two hours whilestirring and heating at 163° C., followed by two hours of nitrogenstripping, then cooling and filtering to give the final product. Thisproduct had a viscosity of 428 cs. at 100° C., a nitrogen content of1.21 wt. %, a boron content of 0.23 wt. % and contained 49.3 wt. % ofthe reaction product, i.e. the material actually reacted, and 50.7 wt. %of unreacted PIB and mineral oil (S150N).

EXAMPLE 2

A PIBSA having a SA:PIB ratio of 1.26 was prepared in a similar mannerto Example 1, Part A, except that 100 parts of polyisobutylene wasreacted with 7.40 parts of chlorine and 10.23 parts of maleic anhydride.The PIBSA had a Sap. No. of 76.7 and was 87.3 wt. % active.

1800 g of the PIBSA (Sap. No. 76.7) was mixed with about 1462 g S150Noil and 145.7 g PAM followed by heating to 149° C. for 1 hour, nitrogenstripping for 1.5 hours, then adding 51.5 g boric acid and heating for 2hours at 163° C. followed by 2 more hours of nitrogen stripping, thencooling and filtering.

The final product contained 1.41 wt. % N; 0.23 wt. % B, and contained52.8 wt. % of the reaction product, with a viscosity of 458 cs. at 100°C.

EXAMPLE 3

PIBSA having a SA:PIB ratio of 1.41 was prepared in the general mannerof Example 1, Part A except that 11.63 parts of maleic anhydride wasmixed with 100 parts of polyisobutylene of 1725 {overscore (M)}_(n) andblown with 8.42 parts of chlorine over 4.5 hours. The PIBSA had a Sap.No. of 84.8 and was about 90.3 wt. % a.i. with 9.7 wt. % unreacted PIB.

1800 g of the PIBSA (SA:PIB ratio of 1.41) was diluted with 1536 g ofS150N oil, and reacted with 161.1 g of the aforesaid PAM for 1 hour at149° C., and nitrogen stripped for 1.5 hours. Then 52.8 g of boric acidwas added over 2 hours while stirring at 163° C. followed by nitrogenstripping for 2 hours, cooling and then filtering.

The product contained 1.49 wt. % N; 0.22 wt. % B; had a viscosity of 574cs. at 100° C. and contained 52.8 wt. % of the reaction product.

EXAMPLE 4

A PIBSA having a SA:PIB ratio of 1.13 was prepared by reacting 100 partsof polyisobutylene (1725 {overscore (M)}_(n)) with 8.12 parts of maleicanhydride by the addition of 6.29 parts of chlorine over 5.5 hours as inExample 1, Part A. The PIBSA had a Sap. No. of 69.3 and contained 85.2wt. % a.i.

In a manner similar to that of Example 3, 1600 parts of the PIBSA(SA:PIB ratio of 1.13, 85.2 wt. % a.i.) was diluted with 1350 parts ofS150N oil and reacted with 118 parts of PAM for 1 hour at 149° C. andnitrogen stripped for 1.5 hours. Then 39.2 parts of boric acid was addedover 1.5 hours while stirring at 163° C. followed by nitrogen strippingfor 2 hours, cooling and then filtering. The final product contained1.24 wt. % N; 0.25 wt. % B, and had a viscosity of 463 cs. at 100° C.and contained 49.1 wt. %. of the reaction product.

EXAMPLE 5

PIBSA having a SA:PIB ratio of 0.97 was prepared in the general mannerof Example 1, Part A but reacting 6.98 parts of maleic anhydride with100 parts of polyisobutylene (1725 mol. wt.) by adding 5.47 parts ofchlorine over 5.5 hours. The resulting PIBSA had a Sap. No. of 59.6, andwas 79.7 wt. % active.

1800 g of the PIBSA was mixed with 1162 g of S150N oil, and reacted with113.2 g of PAM at 149° C. for 1 hour and then nitrogen stripped for 1.5hours. This was followed by the addition of 46 g of boric acid over 2hours at 163° C. followed by 2 hours of stripping while at 163° C. Thefinal product after filtering contained 1.20 wt. % N; 0.24 wt. l 8, andhad a viscosity of 475 cs. at 100° C. and contained 55.6 wt. % of thereaction product.

Additive Interaction Test

The products of Examples 1 to 5 were tested for additive interactioneffects by blending 50 g of said products with a 12.5 g of metaldetergent additive and 12.5 g of S150N and measuring the viscosityinitially and after 24 and 168 hours at 100° C.

Two metal detergents were used in the above tests. Detergent A was a 400TBN (Total Base Number) overbased magnesium sulfonate of about 9 wt. %magnesium lubricating oil additive. Detergent B was a 300 TBN overbasedcalcium sulfonate of about 12 wt. % calcium, lubricating oil additive.The ratio of 4:1:1 for the dispersant:detergent:oil ratio was used so asto give interaction that would not result in gel, but which were largeenough to differentiate between strongly and weakly interacting systems.Also many lubricating formulations have 3 or 4 fold excess of dispersantover detergent.

Table 1, which follows, summarizes the compositions tested and the testresults.

TABLE Additive Interaction Test Viscosity, cs. at 100° C. Deter- 168Dispersant SA:PIB gent Theoretical* Initial 24 hr. 28 hr. hrs. Example 11.04 A 132 203 209 — 246 ″ B 123 185 190 — 242 B 123 187 — 198 244Example 2 1.26 A 137 250 265 — 327 ″ B 129 240 247 — 322 B 129 243 — 266316 Example 3 1.41 A 160 380 413 — 547 ″ B 151 422 454 — 560 B 151 433 —464 565 Example 4 1.13 A 138 224 230 — 210 ″ B 131 211 212 — 264 Example5 0.97 A 141 211 221 — 281 ″ B 133 188 203 — 237 B 133 189 194 — 242*Expected based on blending curves, i.e. based upon the sum of theviscosity effects of each additive component individually in oil withoutinteraction with other additives.

The data in Table I shows that the interaction between the dispersantand metal detergent increases as the SA:PIB ratio goes from a 0.97SA:PIB ratio up to a ratio of 1.41. The interaction, as measured byviscosity increase, accelerates as one moves to the 1.41 ratio. Theinvention is represented by Example 4 in Table I, which at 1.13 SA:PIBratio is within the claimed ranges of the invention, i.e. 1.05 to 1.25,and which gave low interaction between the dispersant and metaldetergent.

EXAMPLE 6

A polyisobutenyl succinic anhydride having a SA:PIB ratio of 1.09 isprepared from polyisobutylene having a number average molecular weightof about 2250. The PIBSA is prepared in a manner similar to that ofExample 1, Part A except that 100 parts by weight of polyisobutylene arereacted with about 5.67 parts of chlorine and about 6.97 parts of maleicanhydride.

The resulting polyisobutenyl succinic anhydride will have a Sap. No. ofabout 52.

1800 parts of the PIBSA are mixed with 1163 parts of S150N and 94 partsof PAM. The mixture is heated to 149° C. for 1 hour and nitrogenstripped at this temperature for 1.5 hours. 36.5 parts of boric acid areadded over 1.5 hours while stirring at 163° C. followed by nitrogenstripping for 2 hours, cooling and filtering.

The product will contain about 0.97 wt. % N and about 0.28 wt. % B.

EXAMPLE 7

A polyisobutenyl succinic anhydride having a SA:PIB ratio of about 1.15is prepared from polyisobutylene having a number average molecularweight of about 1950. The PIBSA is prepared in a manner similar to thatof Example 1, Part A except that about 6.53 parts of chlorine and about8.02 parts of maleic anhydride are used.

The resulting polyisobutenyl succinic anhydride will have a Sap. No. ofabout 62.5 and will be about 84.4 wt. % active.

1800 parts of the PIBSA are mixed with 1328 parts of S150N and 104 partsPAM, heated to 149° C. for 1 hour, stripped by nitrogen blowing for 1.5hours. Then 38 parts of boric acid are added over 1.5 hours while mixingat a temperature of 163° C. This is followed by 2 hours of nitrogenstripping, cooling and filtering. The final product will contain about1.08 wt. % N and 0.26 wt. % B.

EXAMPLE 8

A polyisobutenyl succinic anhydride (PIBSA) having a SA:PIB ratio ofabout 1.15 is prepared from polyisobutylene having a number averagemolecular weight of about 2600. The PIBSA is prepared in a mannersimilar to that of Example 1, Part A, except that 4.9 parts of chlorineand 6 parts of maleic anhydride is used.

The resulting polyisobutenyl succinic anhydride will have a Sap. No. ofabout 43.6 and will be about 73 wt. % active.

1800 parts of the PIBSA is mixed with 992.4 parts of S150N and 83.3parts PAM, heated to 149° C. for 1 hour, stripped by nitrogen blowingfor 1.5 hours. 56 parts of boric acid is then added over 1.5 hours whilemixing at a temperature of 163°. This is followed by 2 hours of nitrogenstripping, cooling and filtering. The final product will contain about0.96 wt. % N and about 0.33 wt. % B.

EXAMPLE 9

A polyisobutenyl succinic anhydride having a SA:PIB ratio of 1.25 isprepared from polyisobutylene having a number average molecular weightof about 2600. The PIBSA is prepared in a manner similar to that ofExample 1, Part A, except that 6.00 parts of chlorine and 7.54 parts ofmaleic anhydride are used.

The resulting polyisobutenyl succinic anhydride will have a Sap. No. ofabout 51.6 and is about 80 wt. % active.

1800 parts of the PIBSA is mixed with 1328 parts of S150N and 100.9parts PAM, heated to 149° C. for 1 hour, stripped by nitrogen blowingfor 1.5 hours. 60 parts of boric acid is then added over 1.5 hours whilemixing at a temperature of 163° C. This is followed by 2 hours ofnitrogen stripping, cooling and filtering. The final product willcontain about 1.07 wt. % N and about 0.32 wt. % B.

EXAMPLE 10

A polyisobutenyl succinic anhydride is prepared from polyisobutylene ofabout 2200 molecular weight to have a SA:PIB ratio of about 1.13,followed by reaction with PAM and boric acid to give a lubricating oildispersant with about 0.25 wt. % boron and about 1.0 wt. % nitrogen.

Engine Tests EXAMPLE 11

Lubricant A was a 10W40 crankcase motor oil and was formulatedcontaining 4.5 vol. % of a dispersant concentrate of a non-borateddispersant product made by reacting PAM with a PIBSA wherein the PIB hada molecular weight of about 1740 and the SA:PIB ratio or functionalitywas 1.19. The PIBSA was made by chlorinating the PIB and then reactingwith maleic anhydride. This concentrate analyzed about 1.27 wt. % N. Theformulation also contained a hydrocarbon type viscosity index improver,a zinc dialkyl dithiophosphate, an overbased 40OTBN magnesium sulfonate,an anti-friction additive and anti-foamant.

Lubricant B was similar to Lubricant A but used 4.5 vol. % of aconcentrate of an ashless dispersant made from a PIBSA having a SA:PIBratio of about 1.3 to 1 using a 1300 mol. wt. PIB. This PIBSA wasreacted with PAM. The concentrate of this dispersant analyzed about 1.46wt. % N.

Lubricants A and B were tested in a MS sequence VD Engine Test. Thistest is well known in the automotive industry. It is described in ASTMDocument for Multigrade Test Sequence for Evaluating Automotive EngineOil, Sequence VD, Part 3 of STP 315H. At the end of each test, variousparts of the engine are rated on a merit basis of 0 to 10, wherein 10represents a perfectly clean part while the lesser numbers representincreasing degrees of deposit formation. The various ratings are thentotaled and averaged on a basis of 10 as a perfect rating. The test iscarried out in a 1980 Model Ford 2.3L 4-cylinder engine under testconditions which simulate “stop and go” city driving and moderatetemperature operations. Cleanliness results obtained with thecompositions described above are given in Table II.

TABLE II MS SEQUENCE VD TEST RESULTS Merit Ratings (Basis 0 to 10) 10W40Lubricants A B Requirements Sludge 9.54 9.50 9.4 Varnish, ave. 6.68 6.356.6 Piston Skirt 6.78 6.77 6.7 Varnish Dispersant conc. 4.5 4.5 vol. %

Table II shows that 4.5 vol. % of the dispersant used in Lubricant B wasinsufficient to pass the test as it did not meet the 6.6 requirement foraverage varnish. On the other hand, 4.5 vol. % of the dispersantconcentrate of the invention met all the requirements of this test, eventhough it had a lower nitrogen concentration.

Improvements in performance are also obtained by the invention whencomparing borated dispersants. Thus, Lubricant A′ was prepared similarto Lubricant A except that 4.5 vol. % of a borated dispersantconcentrate was used wherein the PIB had a molecular weight of 1687, theSA:PIB ratio was 1.18, and the dispersant analyzed 1.21 wt. % nitrogenand 0.28 wt. % boron. Lubricant A′ gave a sludge rating of 9.54, anaverage varnish of 6.98 and a piston skirt varnish rating of 7.14.Lubricant B′ was prepared similar to Lubricant B except that 4.5 vol. %of a borated dispersant concentrate was used wherein the PIB had amolecular weight of 1300, the SA:PIB ratio was 1.31 and the dispersantanalyzed 1.46 wt. % nitrogen and 0.32 wt. % boron. Lubricant B′, as anaverage of several tests in the same engine used for testing LubricantA′, gave a sludge rating of 9.55, average varnish of 6.63 and pistonskirt varnish of 7.06. Using a different engine, Lubricant B′ (ave. ofseveral tests) gave a sludge rating of 9.50, average varnish of 6.44 andpiston skirt varnish of 6.93. Thus, a better average varnish wasobtained by Lubricant A′ which contained dispersant of the invention.

Lubricant C was similar to Lubricant A except that it was a 10W30crankcase oil containing 4.0 vol. % of the dispersant concentrate.Lubricant C also required a lesser amount of the viscosity indeximprover due to its 10W30 viscosity requirements.

Lubricant D was similar to Lubricant C except that it contained 4.0 vol.% of the dispersant concentrate used in Lubricant B.

Lubricants C and D were tested in a Caterpillar 1-H2 Test, but for 120hours rather than the full 480 hour test described in ASTM Document forSingle Cylinder Engine Test for Evaluating the Performance of CrankcaseLubricants, Caterpillar 1-H2 Test Method, Part 1, STP 509A. This testevaluates the ability of diesel lubricants to curtail accumulation ofdeposits on the piston when operating in high severity diesel engines.

The results are shown in Table III.

TABLE III Caterpillar 1-H2 Test - 120 Hours 10W30 Lubricants C D WTD 48154 TGF 11 25

Table III shows that the dispersant of the invention used in Lubricant Awas superior in (TGF) top groove fill and (WTD) weighed total demerits,i.e. deposits, compared with the known dispersant of Lubricant A. Thisfavorable comparison was obtained even though the total nitrogen contentwas only 1.27 nitrogen for Lubricant A as compared to 1.46 wt. %nitrogen for the known dispersant concentrate, thus demonstrating a moreefficient utilization of the higher cost polyamine component of thedispersant.

A Caterpillar 1G-2 Test was carried out, except the test was for 120hours rather than the full 480 hour test described in ASTM Document forSingle Cylinder Engine Test for Evaluating the Performance of CrankcaseLubricants, Caterpillar 1-G2 Test Method, Part 1, STP 509A, on LubricantC′, prepared similarly to Lubricant C except that 4.0 wt. % of theborated dispersant concentrate product of Example 4 was used. LubricantD′ was also tested and was prepared similarly to Lubricant D except thatthe borated dispersant concentrate was of 1300 mol. wt. PBS, with aPIBSA with a SA:PIB ratio of 1.31 and the dispersant analyzed 1.46 wt. %N and 0.32 wt. % B. Lubricant C′ shows a TGF (top groove fill) of 54,and a WTD (weighed total demerits) of 339, which was about comparable tothat of Lubricant D′ which gave a TGF of 57 and a WTD of 324.

Tables II and III show the effectiveness of the dispersant in bothgasoline and diesel engine tests and demonstrate the high engineperformance that can be attained by the higher molecular weight polymercombined with a sufficiently high SA:PIB ratio to form an improveddispersant. Table I shows that too high an SA:PIB ratio can causeundesired viscosity increase and additive interactions. Thus, thepresent invention obtains an unexpected overall improvement inproperties within the select ranges of the invention.

What is claimed is:
 1. A fuel composition comprising (i) a liquidpetroleum fuel and (ii) an oil soluble dispersant comprising an oilsoluble reaction product of a reaction mixture comprising: (a) ahydrocarbyl substituted C₄ to C₁₀ dicarboxylic acid producing materialformed by reacting olefin polymer of C₂ to C₁₀ monoolefin having anumber average molecular weight of about 1500 to 5,000 and a C₄ to C₁₀monounsaturated acid material, wherein the substituted material has afunctionality ratio of from about 1.05 to 1.25 dicarboxylic acidproducing moieties per molecule of said olefin polymer used in thereaction; and (b) a basic reactant selected from the group consisting ofpolyamine, polyhydric alcohol, amino alcohol and mixtures thereof. 2.The fuel composition according to claim 1, wherein (ii) (b) is apolyamine.
 3. The fuel composition according to claim 2, wherein saiddispersant is borated, wherein (ii) (b) is a polyethyleneamine and saidreaction mixture includes boric acid.
 4. The fuel composition accordingto claim 1, wherein (ii) (b) is a polyhydric alcohol.
 5. The fuelcomposition according to claim 1, wherein (ii) (b) is an amino alcohol.6. The fuel composition according to claim 1, wherein the liquidpetroleum fuel is selected from the group consisting of gasoline,kerosene, diesel fuel, home heating fuel oil, and jet fuel.
 7. The fuelcomposition according to claim 6, wherein the dispersant has aconcentration in the range of 0.001 to 0.5 weight percent, based on theweight of the composition.
 8. The fuel composition according to claim 1,wherein the monounsaturated acid material is maleic anhydride.
 9. Thefuel composition according to claim 8, wherein the olefin polymercomprises a member selected from the group consisting of polyisobutyleneand copolymer of butylene and isobutylene.
 10. The fuel compositionaccording to claim 9, wherein the number average molecular weight of theolefin polymer is from about 1500 to 3,000.
 11. The fuel compositionaccording to claim 10, wherein the basic reactant (ii) (b) comprisespolyamine.
 12. The fuel composition according to claim 11, wherein thebasic reactant (ii) (b) comprises polyethyleneamine.
 13. The fuelcomposition according to claim 2, wherein the dispersant is furthertreated with a boron compound selected from the group consisting ofboron oxide, boron halides, boron acids and esters of boron acids toobtain a borated dispersant.
 14. The fuel composition according to claim13, wherein the basic reactant (ii) (b) comprises polyethyleneamine. 15.The fuel composition according to claim 2, wherein the number averagemolecular weight of the olefin polymer is from about 1500 to 3,000. 16.The fuel composition according to claim 15, wherein the substitutedmaterial has a functionality ratio of from about 1.06 to 1.20.
 17. Thefuel composition according to claim 16, wherein the number averagemolecular weight of the olefin polymer is from about 1500 to 2,500. 18.The fuel composition according to claim 17, wherein the monounsaturatedacid material is maleic anhydride.
 19. The fuel composition according toclaim 18, wherein the olefin polymer comprises a member selected fromthe group consisting of polyisobutylene and copolymer of butylene andisobutylene.